Motor vehicles having an internal combustion engine require air for combustion of the fuel. The air needs to be cleansed of dust and other particles prior to entering the combustion chamber. Therefore, air filters are commonly used in the air intake duct to remove impurities from the air. Sufficient airflow through the engine is critical for optimum engine performance. As the filter becomes dirty, airflow through the filter is reduced, which decreases engine efficiency and increases fuel consumption. Therefore, when the air filters become clogged or otherwise saturated by the air impurities, the filters must be cleaned or replaced. Cleaning the air filters rarely returns the filter to its new condition, since many foreign particles cannot be washed or blown from the filter material. Replacement of filters may become expensive. Replacement or cleansing of the filters also requires labor, which adds to the time and cost.
Pre-filters are known for combustion engines, such as disclosed in U.S. Pat. No. 4,265,647. However, such prior art pre-filter assemblies require structural components mounted to the original equipment manufacture (OEM) air supply in the engine compartment of the vehicle. Many vehicles do not have sufficient open space in the engine compartment to accommodate such additional structure. Also, the prior art pre-filter structures may require some of the OEM structure to be removed, and be replaced with the new OEM pre-filter assembly structure. These prior art structures are costly and require time for installation.
Therefore, a primary objective of the present invention is the provision of a simple pre-filter in the air intake duct to extend the life of the primary air filter.
Another objective of the present invention is the provision of a pre-filter which can be quickly and easily mounted inside the air inlet duct for the engine.
A further objective of the present invention is a provision of a polyester fiber pre-filter which can be installed in the OEM air duct of a combustion engine.
Still another objective of the present invention is the provision of a pre-filter and mounting ring which reside within the OEM air duct or combustion engine.
Yet another objective of the present invention is the provision of a pre-filter assembly which requires no additional space in the engine compartment of a vehicle, beyond the space of the OEM air supply channel.
Another objective of the present invention is the provision of a secondary filter upstream from a primary filter in the air supply channel for an internal combustion engine.
A further objective of the present invention is the provision of a pre-filter for an internal combustion engine which is economical to manufacture, and simple and safe to use.
These and other objectives will become apparent from the following Description of the Invention.